This invention relates to a fuel additive composition. More particularly, this invention relates to a fuel additive composition containing an aliphatic amine, a polyolefin and an aromatic ester.
It is well known that automobile engines tend to form deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports and intake valves, due to the oxidation and polymerization of hydrocarbon fuel. These deposits, even when present in relatively minor amounts, often cause noticeable driveability problems, such as stalling and poor acceleration. Moreover, engine deposits can significantly increase an automobile's fuel consumption and production of exhaust pollutants. Therefore, the development of effective fuel detergents or "deposit control" additives to prevent or control such deposits is of considerable importance and numerous such materials are known in the art.
For example, U.S. Pat. No. 3,438,757 to Honnen et al. discloses branched chain aliphatic hydrocarbon N-substituted amines and alkylene polyamines having a molecular weight in the range of about 425 to 10,000, preferably about 450 to 5,000, which are useful as detergents and dispersants in hydrocarbon liquid fuels for internal combustion engines.
U.S. Pat. No. 3,502,451 to Moore et al. discloses motor fuel compositions containing a polymer or copolymer of a C.sub.2 to C.sub.6 unsaturated hydrocarbon or the corresponding hydrogenated polymer or copolymer, wherein the polymer or copolymer has a molecular weight in the range of about 500 to 3,500. This patent further teaches that polyolefin polymers of propylene and butylene are particularly preferred.
U.S. Pat. No. 3,700,598 to Plonsker et al. discloses lubricating oil and fuel compositions containing a small amount of an N-hydrocarbyl-substituted nitrilotris ethylamine, wherein the hydrocarbyl group is preferably a polyolefin group having a molecular weight of about 300 to 20,000, preferably from 500 to 2,000. This patent further teaches that fuel compositions containing this additive will preferably also contain a small amount of a mineral oil and/or a synthetic olefin oligomer having an average molecular weight of about 300 to 2,000.
U.S. Pat. No. 3,756,793 to Robinson discloses a fuel composition containing minor amounts of (A) a polyamine which is the reaction product of a halohydrocarbon having an average molecular weight between 600 to 2500 and an alkylene polyamine, and (B) an organic substance having a viscosity between 20 and 2500 cs. at 20.degree. C. This patent further discloses that a wide variety of compounds are suitable as the organic substance, including polyamines, amides, and esters or mixtures of esters, such as aliphatic diesters of dibasic aliphatic carboxylic acids. Preferred materials for use as the organic substance are described in this patent as polymers or copolymers having an average molecular weight of 300 to 5,000 which are selected from hydrocarbons, substituted hydrocarbons containing oxygen and substituted hydrocarbons containing oxygen and nitrogen. Most preferred polymeric compounds are described in this patent as polyalkylene oxides and polyether glycols.
U.S. Pat. No. 4,173,456 to Scheule et al. discloses a fuel additive composition comprising (A) a hydrocarbon-soluble acylated poly(alkyleneamine) and (B) a normally liquid hydrocarbon-soluble polymer of a C.sub.2 to C.sub.6 olefin, wherein the polymer has an average molecular weight of about 400 to 3,000.
U.S. Pat. No. 4,357,148 to Graiff discloses a motor fuel composition containing an octane requirement increase-inhibiting amount of (a) an oil soluble aliphatic polyamine containing at least one olefinic polymer chain and a molecular weight of about 600 to 10,000 and (b) a polymer and/or copolymer of a monoolefin having 2 to 6 carbon atoms, wherein the polymer has a number average molecular weight of about 500 to 1500.
U.S. Pat. No. 4,832,702 to Kummer et al. discloses a fuel or lubricant composition containing one or more polybutyl or polyisobutylamines. This patent further discloses that, since, in fuel additives, about 50% by weight of the active substance can be replaced by polyisobutene without loss of efficiency, the addition of polyisobutene having a molecular weight of 300 to 2000, preferably from 500 to 1500, is particularly advantageous from the point of view of cost.
U.S. Pat. No. 5,004,478 to Vogel et al. discloses a motor fuel for internal combustion engines which contains an additive comprising (a) an amino- or amino-containing detergent and (b) a base oil which is a mixture of (1) a polyether based on propylene oxide or butylene oxide and having a molecular weight not less than 500, and (2) an ester of a monocarboxylic or polycarboxylic acid and an alkanol or polyol.
U.S. Pat. No. 5,089,028 to Abramo et al. discloses a fuel composition containing an additive which comprises the combination of (1) a polyalkenyl succinimide, (2) a polyalkylene polymer, such as polyisobutylene or polypropylene, (3) an ester of an aliphatic or aromatic carboxylic acid, and (4) a polyether, such as polybutylene oxide, polypropylene or a polybutylene/polypropylene copolymer. The additive may also contain an optional amount of a mineral oil or a synthetic oil.
U.S. Pat. No. 5,242,469 to Sakakibara et al. discloses a gasoline additive composition comprising (A) a monoester, diester or polyolester, and (B) a dispersant selected from (1) a monosuccinimide, (2) a bis-succinimide, (3) an alkylamine having a polyolefin polymer as an alkyl group and an average molecular weight of 500-5,000, and (4) a benzylamine derivative having an average molecular weight of 500-5,000. The additive composition may additionally contain a polyoxyalkylene glycol or its derivative and/or a lubricant oil fraction.
PCT International Patent Application Publication No. WO 92/15656, published Sep. 17, 1992, discloses an additive for gasoline petroleum fuel comprising (A) an oil soluble polyolefin polyamine containing at least one olefinic polymer chain, and (B) a polymer of a C.sub.2 to C.sub.6 monoolefin, wherein the polymer has a number average molecular weight of up to 2,000, and preferably up to 500. This document further discloses that the additive may be used in combination with other additives, including plasticizer esters, such as adipates and mixtures thereof, scavengers, antioxidants, ignition improvers, and metal deactivators.
European Patent Application Publication No. 0,382,159 A1, published Aug. 16, 1990, discloses a liquid hydrocarbon fuel for an internal combustion engine containing a deposit removing and residue inhibiting amount of at least one C.sub.1 to C.sub.4 dialkyl ester of a C.sub.4 to C.sub.6 aliphatic dibasic acid.
European Patent Application Publication No. 0,356,726 A2, published Mar. 7, 1990 discloses fuel compositions containing esters of aromatic di-, tri-, or tetra-carboxylic acids with long-chain aliphatic alcohols or ether alcohols, wherein the alcohols are produced by the hydroformylation of branched olefins, and wherein the total carbon number of the esters is at least 36 carbon atoms and the molecular weight of the esters is 550 to 1,500, preferably 600 to 1,200.
U.S. Pat. No. 4,877,416 to Campbell discloses a fuel composition which contains (A) a hydrocarbyl-substituted amine or polyamine having an average molecular weight of about 750 to 10,000 and at least one basic nitrogen atom, and (B) a hydrocarbyl-terminated poly(oxyalkylene) monool having an average molecular weight of about 500 to 5,000.
It has now been discovered that the unique combination of an aliphatic hydrocarbyl-substituted amine, a polyolefin polymer and an aromatic di- or tri-carboxylic acid ester provides excellent valve sticking performance, while maintaining good control of engine deposits, especially intake valve deposits, when employed as a fuel additive composition for hydrocarbon fuels.